Diamond nitrogen vacancy sensor with dual rf sources

ABSTRACT

Systems and apparatuses are disclosed for providing a uniform RF field to a nitrogen vacancy center diamond.

FIELD BACKGROUND

The present invention relates generally to a sensor assembly of amagnetic sensor.

Magnetic sensors based on a nitrogen vacancy (NV) center in diamond areknown. Diamond NV (DNV) sensors may provide good sensitivity formagnetic field measurements. Such magnetic sensor systems often includecomponents such an optical excitation source, an RF excitation source,and optical detectors. These components are all formed on differentsubstrates or as separate components mechanically supported together.

SUMMARY

Systems and apparatuses are described that use dual radio frequencyelements for providing a uniform magnetic field over an NV diamond. Inone implementation, a magnetic field sensor assembly includes a firstradio frequency (RF) element and a second RF element. An RF feed cableis connected to both the first and second RF elements and provides an RFsignal to the first and second RF elements. A nitrogen-vacancy (NV)center diamond is located between the first RF element and the second RFelement. The first RF element and the second RF element generate amicrowave signal that is uniform over the NV center diamond.

In another implementation, a magnetic field sensor assembly includes afirst radio frequency (RF) element and a second RF element. A first RFfeed cable is connected to first RF element and provides a first RFsignal to the first RF element. A second RF feed cable is connected tothe second RF element and provides a second RF signal to the second RFelement. A nitrogen-vacancy (NV) center diamond located between thefirst RF element and the second RF element. The first RF element and thesecond RF element generate a microwave signal that is uniform over theNV center diamond.

In other implementations, a housing includes the NV diamond, the firstRF element, and the second RF element. In some implementations, ahousing rotational adjustment adjusts a rotation of the NV centerdiamond relative to a light source. In some implementations, a housingposition adjustment adjusts a position of the NV center diamond relativeto a light source. In other implementations, the magnetic field sensorassembly includes both the housing rotational adjustment and the housingposition adjustment.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several implementations in accordance withthe disclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings.

FIG. 1 illustrates one orientation of an NV center in a diamond lattice.

FIG. 2 is an energy level diagram illustrates energy levels of spinstates for the NV center.

FIG. 3 is a schematic illustrating an NV center magnetic sensor system.

FIG. 4 is a graph illustrating the fluorescence as a function of appliedRF frequency of an NV center along a given direction for a zero magneticfield and a non-zero magnetic field.

FIG. 5 is a graph illustrating the fluorescence as a function of appliedRF frequency for four different NV center orientations for a non-zeromagnetic field.

FIG. 6 is a schematic illustrating an NV center magnetic sensor systemin accordance with some illustrative implementations.

FIG. 7. is a schematic illustrating a portion of a DNV sensor with adual RF arrangement in accordance with some illustrativeimplementations.

FIG. 8 is a view of an enclosed DNV sensor with a dual RF arrangement inaccordance with some illustrative implementations.

FIGS. 9A and 9B are schematics of an assembly portion of a DNV sensorwith a dual RF arrangement in accordance with some illustrativeimplementations.

FIG. 10 is a cross-section of a portion of a DNV sensor with a dual RFarrangement in accordance with some illustrative implementations.

FIG. 11 is a schematic illustrating a DNV sensor with a dual RFarrangement in accordance with some illustrative implementations.

FIG. 12 is a cross-section of a DNV sensor with a dual RF arrangement inaccordance with some illustrative implementations.

FIG. 13 is a schematic illustrating a DNV sensor with a dual RFarrangement and laser mounting in accordance with some illustrativeimplementations.

FIG. 14 is a cross-section of a DNV sensor with a dual RF arrangementand laser mounting in accordance with some illustrative implementations.

FIGS. 15A and 15B are schematics of an assembly portion of a DNV sensorwith a dual RF arrangement in accordance with some illustrativeimplementations.

FIGS. 16A and 16B are schematics of an assembly portion of a DNV sensorwith a dual RF arrangement in accordance with some illustrativeimplementations.

DETAILED DESCRIPTION

Nitrogen-vacancy (NV) centers are defects in a diamond's crystalstructure. Synthetic diamonds can be created that have these NV centers.NV centers generate red light when excited by a light source, such as agreen light source, and microwave radiation. When an excited NV centerdiamond is exposed to an external magnetic field the frequency of themicrowave radiation at which the diamond generates red light and theintensity of the light change. By measuring this change and comparingthe change to the microwave frequency that the diamond generates redlight at when not in the presence of the external magnetic field, theexternal magnetic field strength can be determined. Accordingly, NVcenters can be used as part of a magnetic field sensor.

In various implementations, microwave RF excitation is needed in a DNVsensor. The more uniform the microwave signal is across the NV centersin the diamond the better and more accurate an NV sensor will perform.Uniformity, however, can be difficult to achieve. Also, the larger thebandwidth of the element, the better the NV sensor will perform. Largebandwidth, such as octave bandwidth, however, can be difficult toachieve. Various NV sensors respond to a microwave frequency that is noteasily generated by RF antenna elements that are comparable to the smallsize of the NV sensor. In addition, RF elements should reduce the amountof light within the sensor that is blocked by the RF elements. When asingle RF element is used, the RF element is offset from the NV diamondwhen the RF element maximized the faces and edges of the diamond thatlight can enter or leave. Moving the RF element away from the NVdiamond, however, impacts the uniformity of strength of the RF that isapplied to the NV diamond.

The present inventors have realized that the DNV magnetic sensors withdual RF elements described herein provides a number of advantages overmagnetic sensor systems where a single RF element is used. As describedin greater detail below, using a two RF element arrangement in a DNVsensor can allow greater access to the edges and faces of the diamondfor light input and egress, while still exciting the NV centers with auniform RF field. In various implementations, each of the two microwaveRF elements is contained on a circuit board. The RF elements can includemultiple stacked spiral antenna coils. These stacked coils can occupy asmall footprint and can provide the needed microwave RF field in suchthat the RF field is uniform over the NV diamond.

In addition, based upon the spacing and size of the RF elements, alledges and faces of the diamond can be used for light input and egress.The more light captured by photo-sensing elements of a DNV sensorresults in an increased efficiency of the sensor. Variousimplementations use the dual RF elements to increase the amount of lightcollected by the DNV sensor. The dual RF elements can be fed by a singleRF feed or by two separate RF feeds. If there are two RF feeds, thefeeds can be individual controlled creating a mini-phased array antennaeffect, which be enhance the operation of the DNV sensor.

NV Center, its Electronic Structure, and Optical and RF Interaction

The nitrogen vacancy (NV) center in diamond comprises a substitutionalnitrogen atom in a lattice site adjacent a carbon vacancy as shown inFIG. 1. The NV center may have four orientations, each corresponding toa different crystallographic orientation of the diamond lattice.

The NV center may exist in a neutral charge state or a negative chargestate. Conventionally, the neutral charge state uses the nomenclatureNV⁰, while the negative charge state uses the nomenclature NV, which isadopted in this description.

The NV center has a number of electrons including three unpairedelectrons, each one from the vacancy to a respective of the three carbonatoms adjacent to the vacancy, and a pair of electrons between thenitrogen and the vacancy. The NV center, which is in the negativelycharged state, also includes an extra electron.

The NV center has rotational symmetry, and as shown in FIG. 2, has aground state, which is a spin triplet with ³A₂ symmetry with one spinstate m_(s)=0, and two further spin states m_(s)=+1, and m_(s)=−1. Inthe absence of an external magnetic field, the m_(s)=±1 energy levelsare offset from the m_(s)=0 due to spin-spin interactions, and them_(s)=±1 energy levels are degenerate, i.e., they have the same energy.The m_(s)=0 spin state energy level is split from the m_(s)=±1 energylevels by an energy of 2.87 GHz for a zero external magnetic field.

Introducing an external magnetic field with a component along the NVaxis lifts the degeneracy of the m_(s)=±1 energy levels, splitting theenergy levels m_(s)=±1 by an amount 2gμ_(B)Bz, where g is the g-factor,μ_(B) is the Bohr magneton, and Bz is the component of the externalmagnetic field along the NV axis. This relationship is correct for afirst order and inclusion of higher order corrections is a straightforward matter and will not affect the computational and logic steps inthe systems and methods described below.

The NV center electronic structure further includes an excited tripletstate ³E with corresponding m_(s)=0 and m_(s)=±1 spin states. Theoptical transitions between the ground state ³A₂ and the excited triplet³E are predominantly spin conserving, meaning that the opticaltransitions are between initial and final states which have the samespin. For a direct transition between the excited triplet ³E and theground state ³A₂, a photon of red light is emitted with a photon energycorresponding to the energy difference between the energy levels of thetransitions.

There is, however, an alternate non-radiative decay route from thetriplet ³E to the ground state ³A₂ via intermediate electron states,which are thought to be intermediate singlet states A, E withintermediate energy levels. Significantly, the transition rate from them_(s)=±1 spin states of the excited triplet ³E to the intermediateenergy levels is significantly greater than the transition rate from them_(s)=0 spin state of the excited triplet ³E to the intermediate energylevels. The transition from the singlet states A, E to the ground statetriplet ³A₂ predominantly decays to the m_(s)=0 spin state over them_(s)=±1 spin states. These features of the decay from the excitedtriplet ³E state via the intermediate singlet states A, E to the groundstate triplet ³A₂ allows that if optical excitation is provided to thesystem, the optical excitation will eventually pump the NV center intothe m_(s)=0 spin state of the ground state ³A₂. In this way, thepopulation of the m_(s)=0 spin state of the ground state ³A₂ may be“reset” to a maximum polarization determined by the decay rates from thetriplet ³E to the intermediate singlet states.

Another feature of the decay is that the fluorescence intensity due tooptically stimulating the excited triplet ³E state is less for them_(s)=±1 states than for the m_(s)=0 spin state. This is so because thedecay via the intermediate states does not result in a photon emitted inthe fluorescence band, and because of the greater probability that them_(s)=±1 states of the excited triplet ³E state will decay via thenon-radiative decay path. The lower fluorescence intensity for them_(s)=±1 states than for the m_(s)=0 spin state allows the fluorescenceintensity to be used to determine the spin state. As the population ofthe m_(s)=±1 states increases relative to the m_(s)=0 spin, the overallfluorescence intensity will be reduced.

NV Center, or Magneto-Optical Defect Center, Magnetic Sensor System

FIG. 3 is a schematic illustrating a NV center magnetic sensor system300 which uses fluorescence intensity to distinguish the m_(s)=±1states, and to measure the magnetic field based on the energy differencebetween the m_(s)=+1 state and the m_(s)=−1 state. The system 300includes an optical excitation source 310, which directs opticalexcitation to an NV diamond material 320 with NV centers. The system 300further includes an RF excitation source 330 which provides RF radiationto the NV diamond material 320. Light from the NV diamond may bedirected through an optical filter 350 to an optical detector 340.

The RF excitation source 330 may be a microwave coil, for example. TheRF excitation source 330 when emitting RF radiation with a photon energyresonant with the transition energy between ground m_(s)=0 spin stateand the m_(s)=+1 spin state excites a transition between those spinstates. For such a resonance, the spin state cycles between groundm_(s)=0 spin state and the m_(s)=+1 spin state, reducing the populationin the m_(s)=0 spin state and reducing the overall fluorescence atresonance. Similarly resonance occurs between the m_(s)=0 spin state andthe m_(s)=−1 spin state of the ground state when the photon energy ofthe RF radiation emitted by the RF excitation source is the differencein energies of the m_(s)=0 spin state and the m_(s)=−1 spin state. Atresonance between the m_(s)=0 spin state and the m_(s)=−1 spin state, orbetween the m_(s)=0 spin state and the m_(s)=+1 spin state, there is adecrease in the fluorescence intensity.

The optical excitation source 310 may be a laser or a light emittingdiode, for example, which emits light in the green, for example. Theoptical excitation source 310 induces fluorescence in the red, whichcorresponds to an electronic transition from the excited state to theground state. Light from the NV diamond material 320 is directed throughthe optical filter 350 to filter out light in the excitation band (inthe green for example), and to pass light in the red fluorescence band,which in turn is detected by the detector 340. The optical excitationlight source 310, in addition to exciting fluorescence in the diamondmaterial 320, also serves to reset the population of the m_(s)=0 spinstate of the ground state ³A₂ to a maximum polarization, or otherdesired polarization.

For continuous wave excitation, the optical excitation source 310continuously pumps the NV centers, and the RF excitation source 330sweeps across a frequency range which includes the zero splitting (whenthe m_(s)=±1 spin states have the same energy) photon energy of 2.87GHz. The fluorescence for an RF sweep corresponding to a diamondmaterial 320 with NV centers aligned along a single direction is shownin FIG. 4 for different magnetic field components Bz along the NV axis,where the energy splitting between the m_(s)=−1 spin state and them_(s)=+1 spin state increases with Bz. Thus, the component Bz may bedetermined. Optical excitation schemes other than continuous waveexcitation are contemplated, such as excitation schemes involving pulsedoptical excitation, and pulsed RF excitation. Examples, of pulsedexcitation schemes include Ramsey pulse sequence, and spin echo pulsesequence.

In general, the diamond material 320 will have NV centers aligned alongdirections of four different orientation classes. FIG. 5 illustratesfluorescence as a function of RF frequency for the case where thediamond material 320 has NV centers aligned along directions of fourdifferent orientation classes. In this case, the component Bz along eachof the different orientations may be determined. These results alongwith the known orientation of crystallographic planes of a diamondlattice allows not only the magnitude of the external magnetic field tobe determined, but also the direction of the magnetic field.

While FIG. 3 illustrates an NV center magnetic sensor system 300 with NVdiamond material 320 with a plurality of NV centers, in general themagnetic sensor system may instead employ a different magneto-opticaldefect center material, with a plurality of magneto-optical defectcenters. The electronic spin state energies of the magneto-opticaldefect centers shift with magnetic field, and the optical response, suchas fluorescence, for the different spin states is not the same for allof the different spin states. In this way, the magnetic field may bedetermined based on optical excitation, and possibly RF excitation, in acorresponding way to that described above with NV diamond material.

FIG. 6 is a schematic of an NV center magnetic sensor 600, according toan embodiment of the invention. The sensor 600 includes an opticalexcitation source 610, which directs optical excitation to an NV diamondmaterial 620 with NV centers, or another magneto-optical defect centermaterial with magneto-optical defect centers. An RF excitation source630 provides RF radiation to the NV diamond material 620. The NV centermagnetic sensor 600 may include a bias magnet 670 applying a biasmagnetic field to the NV diamond material 620. Light from the NV diamondmaterial 620 may be directed through an optical filter 650 and anelectromagnetic interference (EMI) filter 660, which suppressesconducted interference, to an optical detector 640. The sensor 600further includes a controller 680 arranged to receive a light detectionsignal from the optical detector 640 and to control the opticalexcitation source 610 and the RF excitation source 630.

The RF excitation source 630 may be a microwave coil, for example. TheRF excitation source 630 is controlled to emit RF radiation with aphoton energy resonant with the transition energy between the groundm_(s)=0 spin state and the m_(s)=±1 spin states as discussed above withrespect to FIG. 3.

The optical excitation source 610 may be a laser or a light emittingdiode, for example, which emits light in the green, for example. Theoptical excitation source 610 induces fluorescence in the red, whichcorresponds to an electronic transition from the excited state to theground state. Light from the NV diamond material 620 is directed throughthe optical filter 650 to filter out light in the excitation band (inthe green for example), and to pass light in the red fluorescence band,which in turn is detected by the optical detector 640. The EMI filter660 is arranged between the optical filter 650 and the optical detector640 and suppresses conducted interference. The optical excitation lightsource 610, in addition to exciting fluorescence in the NV diamondmaterial 620, also serves to reset the population of the m_(s)=0 spinstate of the ground state ³A₂ to a maximum polarization, or otherdesired polarization.

The controller 680 is arranged to receive a light detection signal fromthe optical detector 640 and to control the optical excitation source610 and the RF excitation source 630. The controller may include aprocessor 682 and a memory 684, in order to control the operation of theoptical excitation source 610 and the RF excitation source 630. Thememory 684, which may include a nontransitory computer readable medium,may store instructions to allow the operation of the optical excitationsource 610 and the RF excitation source 630 to be controlled.

According to one embodiment of operation, the controller 680 controlsthe operation such that the optical excitation source 610 continuouslypumps the NV centers of the NV diamond material 620. The RF excitationsource 630 is controlled to continuously sweep across a frequency rangewhich includes the zero splitting (when the m_(s)=±1 spin states havethe same energy) photon energy of 2.87 GHz. When the photon energy ofthe RF radiation emitted by the RF excitation source 630 is thedifference in energies of the m_(s)=0 spin state and the m_(s)=−1 orm_(s)=+1 spin state, the overall fluorescence intensity is reduced atresonance, as discussed above with respect to FIG. 3. In this case,there is a decrease in the fluorescence intensity when the RF energyresonates with an energy difference of the m_(s)=0 spin state and them_(s)=−1 or m_(s)=+1 spin states. In this way the component of themagnetic field Bz along the NV axis may be determined by the differencein energies between the m_(s)=−1 and the m_(s)=+1 spin states.

As noted above, the diamond material 620 will have NV centers alignedalong directions of four different orientation classes, and thecomponent Bz along each of the different orientations may be determinedbased on the difference in energy between the m_(s)=−1 and the m_(s)=+1spin states for the respective orientation classes. In certain cases,however, it may be difficult to determine which energy splittingcorresponds to which orientation class, due to overlap of the energies,etc. The bias magnet 670 provides a magnetic field, which is preferablyuniform on the NV diamond material 620, to separate the energies for thedifferent orientation classes, so that they may be more easilyidentified.

FIG. 7 is a schematic illustrating a portion of a DNV sensor 700 with adual RF arrangement in accordance with some illustrativeimplementations. The magnetic sensor shown in FIG. 6 used a single RFexcitation source 630. The DNV sensor 700 illustrated in FIG. 7 uses twoseparate RF elements. A top RF element 704 and a bottom RF element 708are used to provide the microwave RF to the diamond 720. As shown inFIG. 7, the diamond 720 is sandwiched between the two RF elements 704and 708. A space 706 can be used between the RF elements 704 and 708 toall light ingress or egress. In addition light can enter or leave thesensor via spaces 702 and/or 710. Accordingly, light can be shown ontothe diamond 720 from various positions and photo-sensors, such asphotodiodes, can be used in various locations to collect the red lightthat exits the diamond 720.

FIG. 8 is a view of an enclosed DNV sensor with a dual RF arrangement inaccordance with some illustrative implementations. In thisimplementation, the RF elements are located on two circuit boards 812.The diamond, not shown in FIG. 8 but shown as 1020 in FIG. 10, islocated between the circuit boards 812. The RF element can include oneor more spiral elements with n number of loops. For example, each RFelement can include a single spiral with 2, 3, 4, etc., loops. In otherimplementations, the RF element can include multiple spirals, such as 2,3, 4, 5, etc., that are stack on top of one another. In theseimplementations, the number of loops in each spiral can be the same orcan be different. For example, in one implementation, each RF elementcontains five spirals each having four loops. These elements can be madeusing fusion bonded multilayer dielectrics.

A spacer 814 separates the individual circuit boards. The sensorassembly also includes retaining rings 808 and a plastic mounting plate816. The illustrated sensor assembly is contained with a lens tube 804such as a 1 inch ID lens tube. The sensor assembly also contains adirect-current connector 806 that can be used to provide power to thesensor assembly. The assembly also includes a photo sensor 840.

In this illustrated implementation, the RF elements are fed from a RFfeed cable 802, that can be a coaxial cable. The RF feed cable 802attaches to the assembly via an RF connector 810. In otherimplementations, a second RF feed cable can be used. In thisimplementation, each RF element is fed using a separate RF signal.

FIGS. 9A and 9B are schematics of an assembly portion of a DNV sensorwith a dual RF arrangement in accordance with some illustrativeimplementations. The illustrated assembly portion can be used in theimplementation illustrated in FIG. 8. FIG. 9A illustrates one side ofthe assembly. This side includes an ingress portion 902 that allowslight to reach the diamond that is between the RF elements. In thisimplementation, the ingress portion is in the center of the assembly. Inother implementations, the ingress portion can be located between the RFelements along the diameter of the assembly.

FIG. 9B illustrates the opposite side of the assembly shown in FIG. 9A.The circuit board elements that contain the RF elements 914 are shownalong with the space 912 that separates the RF elements. A RF connector910 is shown that provides the RF source signal to the RF elements. Aphoto sensor 940 is also shown in the middle of the assembly. Underneaththe photo sensor is an egress portion. As light is shined through theingress portion 920, the light will pass through the diamond, not shown,that is contained within the assembly between the two RF elements. Thelight will pass through the diamond and exit the opposite side of theassembly and reach the photo sensor 940. The photo sensor can thenmeasure property of the light, such as the light's wavelength.

FIG. 10 is a cross-section of a portion of a DNV sensor with a dual RFarrangement in accordance with some illustrative implementations. Theportion of the DNV sensor is the same as the portion of the assemblyillustrated in FIGS. 9A and 9B and can be used in the DNV sensorillustrated in FIG. 8. The cross section of the sensor assembly is doneas illustrated on the portion of the assembly 1030. The diamond 1020 isnow visible as located between a top RF element 1004 and a bottom RFelement 1008. A spacer 1010 separates the RF elements 1004 and 1008. Theingress portion of the assembly is shown directly above the diamond1020. Light can enter the assembly through this ingress portion and passthrough the diamond 1020. The light that exits the diamond can passthrough the egress portion of the assembly and reach the photo sensor1040. Additional egress portions through the space can also be used.Thus, light can be collected from the face of the diamond and/or throughthe edges of the diamond.

As noted above, the RF elements can be fed by separate RF feeds andlight can be collected from various faces and/or edges of the diamond.FIG. 11 is a schematic illustrating a DNV sensor with a dual RFarrangement in accordance with some illustrative implementations. TheDNV sensor includes a light source and focusing lens assembly 1102. Thelight source can various light sources such as a laser or LED. In FIG.11, the light source is an LED. A heatsink 1108 is used to bleed awaythe heat from the light source. The DNV assembly is housed in an elementstructure 1106 and described in greater detail below. In the illustratedimplementation, the element structure 1160 is fixed within the sensor.As this implementation includes separate RF feeds, two RF cables 1104are provided to the DNV assembly. The RF signal provided to the RFelements can therefore be the same or the feed signals can be different.In some implementations, the RF signals are different based upon theconfiguration of the elements of the NV diamond assembly. For example,if one RF element is slightly further from the NV diamond compared tothe other RF element, different RF signals can be used to take intoaccount the differences in distances.

FIG. 12 is a cross-section of a DNV sensor of FIG. 11 with a dual RFarrangement in accordance with some illustrative implementations.Accordingly, the DNV sensor includes a light source heatsink 1208. Inaddition, elements within the light source and focusing lens assemblyand element structure can be seen. The light source and focusing lensassembly includes an LED 1202 and one or more focusing lenses 1204.Light from the LED 1202 is focused, using the one or more focusinglenses 1204, onto an NV diamond 1220. In this implementation, lightenters an edge of the NV diamond 1220 and is ejected from one or morefaces on the NV diamond 1220. In FIG. 12, light is ejected from both thetop and bottom faces of the NV diamond 1220. Accordingly, there are twophoto-sensor assemblies 1240 and 1242 located above and below the NVdiamond. These photo-sensor assemblies 1240 and 1242 can includephotodiodes that detect the light that is ejected from the NV diamond1220.

The NV diamond is located between two RF elements 1230 and 1232. TheseRF elements provide a microwave RF signal uniformly across the NVdiamond. Light is ejected through the top and bottom face of the NVdiamond 1220 and travels to one of the photo-sensor assemblies 1240 and1242. Between the photo-sensor assemblies 1240 and 1242 there areattenuators 1234. The attenuators reduce or eliminate the RF generatedby the RF elements to avoid interference with other elements of thesensor. Ejected travels through a light pipe 1236 that is between eachphoto-sensor assembly and the NV diamond. In various implementations, atleast a portion of the light pipe is located within the attenuators.Such a configuration allows the photo-sensing array to be positionedcloser to the NV diamond and remain unaffected by the EMI of the sensor.Further description of the benefits of housing a portion of the lightpipe within an attenuator is described in U.S. patent application Ser.No. ______, entitled “Magnetometer with Light Pipe,” filed on the sameday as this application, the contents of which are hereby incorporatedby reference.

FIG. 13 is a schematic illustrating a DNV sensor with a dual RFarrangement and laser mounting in accordance with some illustrativeimplementations. In the illustrated implementation, the light source hasbeen changed to a laser which is included in a laser and focusing lensassembly 1302. In the illustrated implementation, the NV diamond ishoused in an adjustable structure. A rotatable adjustment assembly 1304allows the NV diamond to be rotated. An x-y-z adjustment assembly 1306allows the NV diamond and various elements to be positioned in 3D space.As the NV diamond's position can be changed, there is an x-y adjustmentassembly 1304 that is used to adjust the ingress of light into the NVdiamond assembly.

FIG. 14 is a cross-section of a DNV sensor illustrated in FIG. 13 with adual RF arrangement and laser mounting in accordance with someillustrative implementations. An NV diamond 1420 is located between twoRF elements 1432. Light pipes 1430 provide a path for light that exitsthe faces of the NV diamond 1420 to travel from the NV diamond to one oftwo photo-sensing assemblies 1440. In various implementations, at leasta portion of each light pipe 1430 is housed with an attenuator 1434. Inother implementations, the DNV sensor does not contain the attenuators1434. The rotatable adjustment assembly allows the NV diamond andrelated elements such as the RF elements to be rotated within the NVdiamond assembly. This can allow the light ingress portion of thediamond to be altered as well as altering where light exiting the NVdiamond 1420 is collected. For example, the NV diamond can be rotated toallow light to enter the diamond at an edge or at a face.

The x-y-z adjustment assembly allows the position of the NV diamond andrelated elements within the NV diamond assembly to be changed. Thisassembly allows for the control of where the light will enter the NVdiamond as well as where the ejected light will be collected. The x-yadjustment assembly allows the light source to also be moved such thatthe light can enter the NV diamond assembly regardless of the rotationand position of the NV diamond within the NV diamond assembly.

FIGS. 15A and 15B are schematics of an assembly portion of a DNV sensorwith a dual RF arrangement in accordance with some illustrativeimplementations. FIG. 15A illustrates one side of the assembly portionof the DNV sensor and FIG. 15B illustrates the opposite side of theassembly. In the illustrated implementation, there are two light egressportions 150 and 1510. These portions allow ejected light to leave theassembly and be detected by photo element. The assembly includes two RFelements, a top RF element 1504 and a bottom RF portion 1506. These RFelements can be fed using the same RF signal or can be fed separate RFsignals via the RF connector 1502 and RF connector 1512. The NV diamondis not shown, but is located between the RF elements 1504 and 1506.Light from the light source enters the diamond via a space between theRF elements 1504 and 1506. Light is ejected from the NV diamond viaeither light egress portion 1508 and 1510.

FIGS. 16A and 16B are schematics of an assembly portion of a DNV sensorwith a dual RF arrangement in accordance with some illustrativeimplementations. FIGS. 16A and 16B further illustrate the assemblyportion of the DNV sensor illustrated in FIGS. 15A and 15B. The NVdiamond 1620 is now shown located within a spacer or a diamond alignmentplate, such as a plastic diamond alignment plate. In the illustratedimplementation, light enters between the RF elements. For example, lightcan enter the diamond via the light ingress portion 1610 of theassembly. The RF elements 1602 and 1604 are shown in FIG. 16A along withthe RF feed cable connectors 1606 and 1608.

The foregoing description is provided to enable a person skilled in theart to practice the various configurations described herein. While thesubject technology has been particularly described with reference to thevarious figures and configurations, it should be understood that theseare for illustration purposes only and should not be taken as limitingthe scope of the subject technology. In some aspects, the subjecttechnology may be used in various markets, including for example andwithout limitation, advanced sensors and mobile space platforms.

There may be many other ways to implement the subject technology.Various functions and elements described herein may be partitioneddifferently from those shown without departing from the scope of thesubject technology. Various modifications to these embodiments may bereadily apparent to those skilled in the art, and generic principlesdefined herein may be applied to other embodiments. Thus, many changesand modifications may be made to the subject technology, by one havingordinary skill in the art, without departing from the scope of thesubject technology.

Phrases such as an aspect, the aspect, another aspect, some aspects, oneor more aspects, an implementation, the implementation, anotherimplementation, some implementations, one or more implementations, anembodiment, the embodiment, another embodiment, some embodiments, one ormore embodiments, a configuration, the configuration, anotherconfiguration, some configurations, one or more configurations, thesubject technology, the disclosure, the present disclosure, othervariations thereof and alike are for convenience and do not imply that adisclosure relating to such phrase(s) is essential to the subjecttechnology or that such disclosure applies to all configurations of thesubject technology. A disclosure relating to such phrase(s) may apply toall configurations, or one or more configurations. A disclosure relatingto such phrase(s) may provide one or more examples. A phrase such as anaspect or some aspects may refer to one or more aspects and vice versa,and this applies similarly to other foregoing phrases

A reference to an element in the singular is not intended to mean “oneand only one” unless specifically stated, but rather “one or more.” Theterm “some” refers to one or more. Underlined and/or italicized headingsand subheadings are used for convenience only, do not limit the subjecttechnology, and are not referred to in connection with theinterpretation of the description of the subject technology. Allstructural and functional equivalents to the elements of the variousembodiments described throughout this disclosure that are known or latercome to be known to those of ordinary skill in the art are expresslyincorporated herein by reference and intended to be encompassed by thesubject technology. Moreover, nothing disclosed herein is intended to bededicated to the public regardless of whether such disclosure isexplicitly recited in the above description.

What is claimed is:
 1. A magnetic field sensor assembly comprising: afirst radio frequency (RF) element; a second RF element; an RF feedcable operably connected to first RF element and the second RF elementthat provides an RF signal to the first RF element and the second RFelement; and a nitrogen-vacancy (NV) center diamond located between thefirst RF element and the second RF element, wherein the first RF elementand the second RF element generate a microwave signal that is uniformover the NV center diamond.
 2. The magnetic field sensor assembly ofclaim 1, further comprising a spacer between the first RF element andthe second RF element that separates the first RF element and the secondRF element.
 3. The magnetic field sensor assembly of claim 1, furthercomprising: a first circuit board that includes the first RF element,wherein the first circuit board comprises a light ingress portion thatallows light to travel through the first circuit board including thefirst RF element via the light ingress portion; and a second circuitboard that includes the second RF element, wherein the second circuitboard comprises a light egress portion that allows light to travelthrough the second circuit board including the second RF element via thelight egress portion.
 4. The magnetic field sensor assembly of claim 3,further comprising a photo sensor that receives the light that egressesfrom the light egress portion.
 5. The magnetic field sensor assembly ofclaim 2, further comprising a light ingress portion within the spacerthat allows light to travel through the spacer to the NV diamond.
 6. Themagnetic field sensor assembly of claim 5, further comprising: a firstcircuit board that includes the first RF element, wherein the firstcircuit board comprises a first light egress portion that allows lightto travel through the first circuit board including the first RF elementvia the first light egress portion; and a second circuit board thatincludes the second RF element, wherein the second circuit boardcomprises a second light egress portion that allows light to travelthrough the second circuit board including the second RF element via thesecond light egress portion.
 7. The magnetic field sensor assembly ofclaim 6, further comprising: a first photo sensing assembly thatreceives light from the NV diamond via the first light egress portion;and a second photo sensing assembly that receives light from the NVdiamond via the second light egress portion.
 8. A magnetic field sensorassembly comprising: a first radio frequency (RF) element; a second RFelement; a first RF feed cable operably connected to first RF elementthat provides a first RF signal to the first RF element; a second RFfeed cable operably connected to the second RF element that provides asecond RF signal to the second RF element; and a nitrogen-vacancy (NV)center diamond located between the first RF element and the second RFelement, wherein the first RF element and the second RF element generatea microwave signal that is uniform over the NV center diamond.
 9. Themagnetic field sensor assembly of claim 8, wherein the first RF signalis the same as the second RF signal.
 10. The magnetic field sensorassembly of claim 8, wherein the first RF signal is different from thesecond RF signal.
 11. The magnetic field sensor assembly of claim 8,further comprising a spacer between the first RF element and the secondRF element that separates the first RF element and the second RFelement.
 12. The magnetic field sensor assembly of claim 8, furthercomprising: a first circuit board that includes the first RF element,wherein the first circuit board comprises a light ingress portion thatallows light to travel through the first circuit board including thefirst RF element via the light ingress portion; and a second circuitboard that includes the second RF element, wherein the second circuitboard comprises a light egress portion that allows light to travelthrough the second circuit board including the second RF element via thelight egress portion.
 13. The magnetic field sensor assembly of claim12, further comprising a photo sensor that receives the light thategresses from the light egress portion.
 14. The magnetic field sensorassembly of claim 11, further comprising a light ingress portion withinthe spacer that allows light to travel through the spacer to the NVdiamond.
 15. The magnetic field sensor assembly of claim 14, furthercomprising: a first circuit board that includes the first RF element,wherein the first circuit board comprises a first light egress portionthat allows light to travel through the first circuit board includingthe first RF element via the first light egress portion; and a secondcircuit board that includes the second RF element, wherein the secondcircuit board comprises a second light egress portion that allows lightto travel through the second circuit board including the second RFelement via the second light egress portion.
 16. The magnetic fieldsensor assembly of claim 15, further comprising: a first photo sensingassembly that receives light from the NV diamond via the first lightegress portion; and a second photo sensing assembly that receives lightfrom the NV diamond via the second light egress portion.
 17. A magneticfield sensor assembly comprising: a first radio frequency (RF) element;a second RF element; an RF feed cable operably connected to first RFelement and the second RF element that provides an RF signal to thefirst RF element and the second RF element; a nitrogen-vacancy (NV)center diamond located between the first RF element and the second RFelement, wherein the first RF element and the second RF element generatea microwave signal that is uniform over the NV center diamond; a housingthat houses the NV diamond, the first RF element, and the second RFelement; and a housing position adjustment that adjusts a position ofthe NV center diamond relative to a light source.
 18. The magnetic fieldsensor assembly of claim 17, further comprising a spacer between thefirst RF element and the second RF element that separates the first RFelement and the second RF element.
 19. The magnetic field sensorassembly of claim 17, further comprising: a first circuit board thatincludes the first RF element, wherein the first circuit board comprisesa light ingress portion that allows light to travel through the firstcircuit board including the first RF element via the light ingressportion; and a second circuit board that includes the second RF element,wherein the second circuit board comprises a light egress portion thatallows light to travel through the second circuit board including thesecond RF element via the light egress portion.
 20. The magnetic fieldsensor assembly of claim 19, further comprising a photo sensor thatreceives the light that egresses from the light egress portion.
 21. Themagnetic field sensor assembly of claim 18, further comprising a lightingress portion within the spacer that allows light to travel throughthe spacer to the NV diamond.
 22. The magnetic field sensor assembly ofclaim 21, further comprising: a first circuit board that includes thefirst RF element, wherein the first circuit board comprises a firstlight egress portion that allows light to travel through the firstcircuit board including the first RF element via the first light egressportion; and a second circuit board that includes the second RF element,wherein the second circuit board comprises a second light egress portionthat allows light to travel through the second circuit board includingthe second RF element via the second light egress portion.
 23. Themagnetic field sensor assembly of claim 22, further comprising: a firstphoto sensing assembly that receives light from the NV diamond via thefirst light egress portion; and a second photo sensing assembly thatreceives light from the NV diamond via the second light egress portion.24. A magnetic field sensor assembly comprising: a first radio frequency(RF) element; a second RF element; an RF feed cable operably connectedto first RF element and the second RF element that provides an RF signalto the first RF element and the second RF element; a nitrogen-vacancy(NV) center diamond located between the first RF element and the secondRF element, wherein the first RF element and the second RF elementgenerate a microwave signal that is uniform over the NV center diamond;a housing that houses the NV diamond, the first RF element, and thesecond RF element; and a housing rotational adjustment that adjusts arotation of the NV center diamond relative to a light source.
 25. Themagnetic field sensor assembly of claim 24, further comprising a spacerbetween the first RF element and the second RF element that separatesthe first RF element and the second RF element.
 26. The magnetic fieldsensor assembly of claim 24, further comprising: a first circuit boardthat includes the first RF element, wherein the first circuit boardcomprises a light ingress portion that allows light to travel throughthe first circuit board including the first RF element via the lightingress portion; and a second circuit board that includes the second RFelement, wherein the second circuit board comprises a light egressportion that allows light to travel through the second circuit boardincluding the second RF element via the light egress portion.
 27. Themagnetic field sensor assembly of claim 26, further comprising a photosensor that receives the light that egresses from the light egressportion.
 28. The magnetic field sensor assembly of claim 25, furthercomprising a light ingress portion within the spacer that allows lightto travel through the spacer to the NV diamond.
 29. The magnetic fieldsensor assembly of claim 28, further comprising: a first circuit boardthat includes the first RF element, wherein the first circuit boardcomprises a first light egress portion that allows light to travelthrough the first circuit board including the first RF element via thefirst light egress portion; and a second circuit board that includes thesecond RF element, wherein the second circuit board comprises a secondlight egress portion that allows light to travel through the secondcircuit board including the second RF element via the second lightegress portion.
 30. The magnetic field sensor assembly of claim 29,further comprising: a first photo sensing assembly that receives lightfrom the NV diamond via the first light egress portion; and a secondphoto sensing assembly that receives light from the NV diamond via thesecond light egress portion.
 31. A magnetic field sensor assemblycomprising: a first radio frequency (RF) element; a second RF element; afirst RF feed cable operably connected to first RF element that providesa first RF signal to the first RF element; a second RF feed cableoperably connected to the second RF element that provides a second RFsignal to the second RF element; a nitrogen-vacancy (NV) center diamondlocated between the first RF element and the second RF element, whereinthe first RF element and the second RF element generate a microwavesignal that is uniform over the NV center diamond; a housing that housesthe NV diamond, the first RF element, and the second RF element; and ahousing position adjustment that adjusts a position of the NV centerdiamond relative to a light source.
 32. The magnetic field sensorassembly of claim 31, wherein the first RF signal is the same as thesecond RF signal.
 33. The magnetic field sensor assembly of claim 31,wherein the first RF signal is different from the second RF signal. 34.The magnetic field sensor assembly of claim 31, further comprising aspacer between the first RF element and the second RF element thatseparates the first RF element and the second RF element.
 35. Themagnetic field sensor assembly of claim 31, further comprising: a firstcircuit board that includes the first RF element, wherein the firstcircuit board comprises a light ingress portion that allows light totravel through the first circuit board including the first RF elementvia the light ingress portion; and a second circuit board that includesthe second RF element, wherein the second circuit board comprises alight egress portion that allows light to travel through the secondcircuit board including the second RF element via the light egressportion.
 36. The magnetic field sensor assembly of claim 35, furthercomprising a photo sensor that receives the light that egresses from thelight egress portion.
 37. The magnetic field sensor assembly of claim34, further comprising a light ingress portion within the spacer thatallows light to travel through the spacer to the NV diamond.
 38. Themagnetic field sensor assembly of claim 37, further comprising: a firstcircuit board that includes the first RF element, wherein the firstcircuit board comprises a first light egress portion that allows lightto travel through the first circuit board including the first RF elementvia the first light egress portion; and a second circuit board thatincludes the second RF element, wherein the second circuit boardcomprises a second light egress portion that allows light to travelthrough the second circuit board including the second RF element via thesecond light egress portion.
 39. The magnetic field sensor assembly ofclaim 38, further comprising: a first photo sensing assembly thatreceives light from the NV diamond via the first light egress portion;and a second photo sensing assembly that receives light from the NVdiamond via the second light egress portion.
 40. A magnetic field sensorassembly comprising: a first radio frequency (RF) element; a second RFelement; a first RF feed cable operably connected to first RF elementthat provides a first RF signal to the first RF element; a second RFfeed cable operably connected to the second RF element that provides asecond RF signal to the second RF element; a nitrogen-vacancy (NV)center diamond located between the first RF element and the second RFelement, wherein the first RF element and the second RF element generatea microwave signal that is uniform over the NV center diamond; a housingthat houses the NV diamond, the first RF element, and the second RFelement; and a housing rotational adjustment that adjusts a rotation ofthe NV center diamond relative to a light source.
 41. The magnetic fieldsensor assembly of claim 40, wherein the first RF signal is the same asthe second RF signal.
 42. The magnetic field sensor assembly of claim40, wherein the first RF signal is different from the second RF signal.43. The magnetic field sensor assembly of claim 40, further comprising aspacer between the first RF element and the second RF element thatseparates the first RF element and the second RF element.
 44. Themagnetic field sensor assembly of claim 40, further comprising: a firstcircuit board that includes the first RF element, wherein the firstcircuit board comprises a light ingress portion that allows light totravel through the first circuit board including the first RF elementvia the light ingress portion; and a second circuit board that includesthe second RF element, wherein the second circuit board comprises alight egress portion that allows light to travel through the secondcircuit board including the second RF element via the light egressportion.
 45. The magnetic field sensor assembly of claim 44, furthercomprising a photo sensor that receives the light that egresses from thelight egress portion.
 46. The magnetic field sensor assembly of claim43, further comprising a light ingress portion within the spacer thatallows light to travel through the spacer to the NV diamond.
 47. Themagnetic field sensor assembly of claim 46, further comprising: a firstcircuit board that includes the first RF element, wherein the firstcircuit board comprises a first light egress portion that allows lightto travel through the first circuit board including the first RF elementvia the first light egress portion; and a second circuit board thatincludes the second RF element, wherein the second circuit boardcomprises a second light egress portion that allows light to travelthrough the second circuit board including the second RF element via thesecond light egress portion.
 48. The magnetic field sensor assembly ofclaim 47, further comprising: a first photo sensing assembly thatreceives light from the NV diamond via the first light egress portion;and a second photo sensing assembly that receives light from the NVdiamond via the second light egress portion.
 49. A magnetic field sensorassembly comprising: a first radio frequency (RF) element; a second RFelement; an RF feed cable operably connected to first RF element and thesecond RF element that provides an RF signal to the first RF element andthe second RF element; a nitrogen-vacancy (NV) center diamond locatedbetween the first RF element and the second RF element, wherein thefirst RF element and the second RF element generate a microwave signalthat is uniform over the NV center diamond; a housing that houses the NVdiamond, the first RF element, and the second RF element; a housingposition adjustment that adjusts a position of the NV center diamondrelative to a light source; and a housing rotational adjustment thatadjusts a rotation of the NV center diamond relative to the lightsource.
 50. The magnetic field sensor assembly of claim 24, furthercomprising a spacer between the first RF element and the second RFelement that separates the first RF element and the second RF element.51. A magnetic field sensor assembly comprising: a first radio frequency(RF) element; a second RF element; a first RF feed cable operablyconnected to first RF element that provides a first RF signal to thefirst RF element; a second RF feed cable operably connected to thesecond RF element that provides a second RF signal to the second RFelement; a nitrogen-vacancy (NV) center diamond located between thefirst RF element and the second RF element, wherein the first RF elementand the second RF element generate a microwave signal that is uniformover the NV center diamond; a housing that houses the NV diamond, thefirst RF element, and the second RF element; a housing positionadjustment that adjusts a position of the NV center diamond relative toa light source; and a housing rotational adjustment that adjusts arotation of the NV center diamond relative to the light source.
 52. Themagnetic field sensor assembly of claim 51, wherein the first RF signalis the same as the second RF signal.
 53. The magnetic field sensorassembly of claim 51, wherein the first RF signal is different from thesecond RF signal.